Mechanical rabble device



L. B( SKINNER.

MECHANICAL RABBLE DEVICE.

APPLICATION man sEPT.z.192vo.

Patented Jan. 31,1922.

2 SHEETS-SHEET l.

L. B. SKINNER.

MECHANICAL RABBLE DEVICE. APPLlcATloN msn sE'PLz. 1920'.

Patented Jan. 31, 1922.

2 SHEETS-SHEET 2.

narran @fr v sereni? aerien,

LEWIS BAILEY SKINNER, OF DENTI-(ER, COLORADO.

MECHANCAL BABELE DEVICE.

Specification of Letters Patent. l Patented Jan. 31, 1922.

application flied september aisee. serial no. 407,702.

'ble devices for use inproasting and calcining furnaces-generally wherein heated ma-,

terial is stirred andadvanced along` a hearth.

The invention has to do especially with rabble mechanism wherein a revoluble upright shaft carries one or more transverse arms mounted atright angles to the shaftand adapted to support a plurality of rabble teeth (also termed rakes, shoes or plows), eacharm comprising `portions extending in diametrically opposite directions from said shaft, and both these oppositely extending portions being adapted and arranged to support the rabble teeth above referred to. Rabble mechanism of this design has certain practical advantages, among which may be mentioned the fact that, where the rabbling of viscous vor sticky material is involved, the rabble teeth may be spaced apart along the supporting double arm sutliciently to largely prevent the viscous material from bridging across, without lessening the effectiveness of the rabbling; performed or reducing the hearth Iarea swept by a single rabble arm carrying the same number of teethclose together.

The present improvements relate to a double arm rabble structure of the'general character described in which said oppositely extending arm portions are combined in `an integral unit of sturdy, rugged construction of particularly advantageous design, which can be assembled `with the upright supporting shaft, or removed therefrom',

easily, expeditiously, and with a minimum interruption to normal furnace operation.

l\lotwithstanding` what has been accom plished in the Way of providing rabble apparatus that will stand up under the ,severe conditions of heat and corrosion to which..

such apparatus is subjected in service,'more or less rapid deterioration of Ythe rabble parts exposed to mechanical wear and corrosive influences in the furnace isinevitable;

so that fairly frequent repair'and replace-V ment must be expected and provided for in actual practice. This is particularly true of the rabble teeth themselves, since the conditions of service tvo-which they are subjected are especially severe and cause relatively rapid destruction of themetal castings commonly employed for these members.

-Removal and replacement kof the rabble teeth and arms necessitates stopping or checkingfurnace operation for a period of time-Whose length depends upon the facility and expedition with which the required changes can be made. lVhile the changes are being` made, thefurnace doors havefto be open to afford access to the rabbles. This subjects the workmen to heat and obnoxious gases; andvit also dilutes and thus lowers the value of the furnace gases by admitting false air into the furnace.` It is important, therefore, to reduce to a minimum the time required to remove and replace defective rabble parts.

Accordingly it is a general object of this invention to provide `impro/*ed double arm rabble apparatus characterized by features of construction enabling` the `double arm a unit to be assembled with. or removed from its upright actuating shaft `easily and eX- 'peditiously, the arrangement beingv such 'ing andother desirable characteristics in a rabble mechanism having provision for internal cooling, while at the same time attaining simplicity and ruggedness in a construction relatively free from liability to get out of order.

With the foregoing objects in view, as well as others which will become apparent hereinafter, the invention comprises the features, details of construction, and combinations of parts, `which will first be described in connection with a typical practical embodiment illustrated in the accompanying` drawings and Will then be more particularly pointed out.

` Generally described, apparatus constructi ed in accordance with the principles of the invention comprises an upright revoluble shaft transversely apertured to receive a rabble arm which can be thrust longitudinally through` the transverse aperture of the shaft until abutment means carried by said rabble arm intermediate its ends, specically an approximately central enlargement, most desirably of circular cross-section and having a tapered bearing surface, engages a coacting surface in the apertured portions of said shaft. Operative engagement of these surfaces denotes proper relative po-sitioning of the parts, which may be locked in this position in any suitable manner, but most desirably by means cooperating with detachable rabble teeth subsequently strung on that portion of the double arm that was thrust through the shaft` aperture to draw the-arm and' shaft abutment surfaces more iirmly together, while also aiding to retain c may be termed a -T rabble arm, which I have found to offer important practical advantages whe-n used in mechanical furnaces for making muriatic acid. and salt cake, such for example as those illustrated in my prior copending applications Serial No. 359,955, filed February 19, 1920, and Serial No. 360,949, filed February 24, 1920. lVhile this specific application of the invention is here pointed out for purposes of illustration, it is not to be inferred that the invention is limited thereto. On the contrary rabbling mechanism embodying the present invention in widely differing' specific forms may be employed in Aore roasting and other "mechanical furnaces or kilns.

snugly wit-hin a correspondingly tapered supporting socket 14 disposed transversely at'the. lower end of the rabble shaft. As

shown, the horizontal rabble arm. projects a substantial distance in opposite directions from said socket, both projecting portions, which in this instance are of unequal length, being adapted and arranged to carry detachable rabble teeth 15. The rabble arm is mounted in position on the upright shaft by thrusting that portion of the arm on the side next the smaller end of the tapered boss 13 at the left in Figs. 1 and 4) through the supporting socket until the cooperating surfaces of the boss and socket engage, that portion of the rabble arm being so dimensioned that it will pass freely through the socket. It will be understood that the rabble teeth are not mounted on the arm until after the latter is assembled with its shaft, since the inside diameter of the receiving socket on the rabble shaft is only large enough to permit the passage therethrough of the arm alone, or rather that portion of the arm extending from the smaller end of the tapered boss. I have found it desirable, in order to reduce the cost of ymanufacture and insure an air-tight seal, to only finish ofi' the marginal portions of the boss 13 and socket 14, the metal between these portions being roughed down slightly below the surfaces of the finished portions to insure contact between the faces 16 and 17 formed on the boss 13 and socket 14, respectively, as shown in Figures 4 and 5.

Means shoul d also be provided to prevent accidental longitudinal movemfent of the rabble arm in the socket. This may be accomplished in various ways within the broad scope of the invention, but the particular arrangement for this purpose shown in the drawings offers important practical advantages and is at present considered Vmost desirable. The teeth 15 and interposed spacer 18, each provided with an ttaching yoke 19 having` hooks 20 fitting over longitudinal supporting ribs or ledges 21 and slidable therealong, are strung on over the end of 'the arm until hub 22 of the inner tooth of the series is received between a pair of locking` lugs 14a on the smaller end of the tapered socket 14 and abuts said socket. A wedge shaped key 23 is then inserted into a slot or key-way 24 provided in the rabble arm andliesl in a groove 25in the outer face 22L of the hub of the outermost toothv of the series. When driven into place, the key bearsl against the end tooth (or spacer) hub and ,forces the series against the socket on the'rabble shaft, drawing the rabble arm boss firmly into the mounting socket and holding the parts solid. The wedge, besides locking the rabble arm to the upright shaft as described, performs the additional function in this instance of holding the teeth and `spacer in place on that portion of the rabble arm so that they cannot accidentally work :off the end of the arm. The series of teeth lrecession and spacers on that portion of the rabble arm on the opposite side of the shaft l() are similarly mounted in place and may be held aga-inst dislodgrnent by means of an. angular stop-pin 26, inserted in an aperture QT, provided in the end of the rabble arm`r the outer face 22 of the end tooth hub being grooved to receive said stop pin.

t will be. observed that the teeth carried by the rabble arm on one side of the shaft l() are in staggered or offset relation radially to those on the opposite side, so that the teeth move in different paths and are arranged to sweep over a plurality of concentric contiguous annular hearth areas making' up the total circular hearth areaivhich the rabble mechanism is designed to cover. By spacing the teeth a considerable distance apart as shown, diiiieulties due to semi-fused sticky material bridging across from one tooth to the next are largely eliminated. This rela-tively wide spacing apart of the rabble teeth is made possible by' the double arm construction; and by suspending the rabble teeth off-center. as shown in Figs. 2 and 8 bridging up and down is also largely done away with. The rabble shaft l0 is rotated in such direction that in operation the tooth edges 15a/are the front or advance edges.

The rabble shaft and arm are 'provided interiorly with cooling passages through which a cooling medium may be circulated. The rabble arm l2 is hollow `and is provided interiorly with a partition wall 28, which divides the space inside linto two pas sages 29 and 3() communicating only near the opposite ends of the arm as shown at 31 and 32. The tapered boss 13 of the hollow rabble arm l2 is provided with openings 38 and 34 communicating with passages 2Q and 30, respectively, and lying on opposite sides of the partition wall 28, the upper edge 35 of which is therefore exposed in this locality. The hollow interior of rabble shaft l0 is divided by the partition wall 3G to forni two independent passa-ges 3T and 38. llVhen the tapered boss 13 of the hollow rabble arm is properly positioned in the receiving socket 14C of the rabble shaft, the lower edge 39 of division wall 36 of the rabble shaft and the free upper edge 35 of wall 28 in the tapered boss abut, so that passage 37 registers with opening 83 and passage 3S registers with opening 3d. Thus a cooling medium such as air for example, may enter the rabble shaft through passage 37 and after passing successively through passages 29, i1-32, and 30 of the rabble arm, flows into passage 38 of the rabble shaft and may be discharged thence through opening LO.

It will be seen that the described construction makes it possible to assemble the double arm rabble member with its shaft by a direct straight thrust movement which is automatically stopped at the proper point necessary to ensure correct alinement and relative positioning of the several parts; and that the assemblage can be held together rigidly by simple rlockingmeans. YRemoval of the rabble arm is also readily effected by driving 'out the key 23, sliding off the ral'ible teeth and spacer, and then driving the arm boss out of the shaft socket by sledging on the end of the arm.

"What l claim is:

l. Rabbling apparatus comprising, in combination, a rabble shaft provided with a transversely disposed socket, a one-piece rabble arm having an integral enlargement in termediate its ends fitting said socket snugly and dividing said arm into two portions, both of which are adapted to carry rabble teeth, and one of which is adapted to be passed through said socket until said enlargement abuts said shaft, and means for locking the rabble arm in this position.

f2. Rabbling appa atus comprising, in combination, a rabble shaft, a rabble arm detachably mounted in said shaft and projecting transversely through the sha-ft, the oppositely projecting portions of said rabble arm being adaptedto carry teeth, means integral with the arm to prevent relative movement in one direction of the rabble shaft and arm, and removable means carried by the rabble arm "to prevent relative movement of Y the rabble shaft and arm in the other direction.

3. Rabbling apparatus comprising, in combination, a rabble shaft, a one-piece rabble arm de taehably mounted on said'shatt and projecting transversely through the shaft, the oppositely projecting portions of -said rabble arm being adapted to carry teeth,

and means for clamping` teeth on said rabble arm, said means also locking the rabble arm against movement on said rabblel shaft. d. Rabbling apparatus comprising, in combination, a rabble shaft provided with a transversely disposed tapered socket, a rabble arm having a. tapered boss fitting in said socket, teeth carried by said rabble arm, means for securing said teeth on said rabble arm, said means also locking said rabble arm in said socket.

Rabbling apparatus comprising, in combination, a rabble shaft provided with a transversely disposed tapered socket, a rah ble arm passing through said socket and having a tapered boss engaging said tapered socket, the rabble arm extending in opposite directions from said rabble shaft, teeth supported by said arm on opposite sides of said boss, and means carriedk by the rabble arm to force teeth against the rabble shaft' and thereby to maintain the rabble arm in said socket.

6. Rabbling apparatus comprising, in combination, a rabble shaft provided with a shaft to maintain the rabble arm in the.

socket.

7. Rabbling apparatus comprising, in combination, a rabble shaft provided with a transversely disposed tapered socket, a rabble arm having a tapered boss, Vsaid arm bef ing adapted to be passed through said socket until said boss engages said socket, teeth supported on said rabble arm, the end'of said rabble arm being slotted, and a wedge in the slot forcing said teeth against said rabble shaft to maintain the rabble arm in said socket. Y

8. Rabbling apparatus comprising, in combination, a rabble sha-ft, a rabble arm removably mounted on said shaft and projecting transversely therethrough, means integral with the arm to prevent longitudinal movement of the arm in one direction in respect to the shaft, removable means carried by the rabble arm to prevent longitudinal movement of the rabble arm in the other direction with respect to the rabble shaft, and means to prevent torsional movement of the rabble arm in respect to the rabble shaft.

9. `Rabbling apparatus comprising, in combination, a hollow shaft divided by a. vertical partition into two passages, a. transverse rabble arm removably mounted on said shaft and having two passages formed by a partition extending to points adjacent each end of the rabble arm, said rabble arm having portions supporting teeth extending on opposite sides of said shaftl and being provided with openings intermediate .said portions communicating respectively with the passages in said arm, and means carried by the rabble arm for locking said arm to the shalft with the partition of the rabble arm in line with the partition of the shaft and abutting therewith,

whereby said openings register with the rel Y said tapered socket, said rabble arm having two passages formed by a vertically disposed partition extending to points adjacent each end of the rabble arm, the tapered boss on said rabble arm being provided with centralopenings communicating respectively with the passages in said arm, and means carried by the rabble arm for` locking said tapered boss in said tapered socket with the vertical partition olf the rabble arm in line with the vertical partition of the shaft and abutting therewith, whereby said central openings register with the respective shaft passages.

ll. Rabbling apparatus comprising, in combination, a rabble shaft having a transverse Vaperture providing a mounting socket, a unitary rabble arm having a centrally disposed enlargement formed to be seated snugly and solidly within said socket by a direct thrust movement of said arm parallel to the axis of said socket, said enlargement dividing the `arm into two portions both adapted and arranged to support rabble teeth, and means preventing dislodgment of said arm lfrom said socket.

ln testimony whereof l hereunto atfix my signature.

LEVVIS BAILEY SKINNER. 

